Postural stability or balance comprises ability to maintain oneself in a correct and proper posture with an ability to prevent oneself from falling. Maintenance of the vertical body posture and its control are complex and comprises of mobility and correction processes from brain, hip, shoulders etc. Postural balance may be affected by progressive and chronic degenerative changes within the structures of nervous system that control motor function, the visual system, hearing, proprioception, and balance. Patients become prone to falls, especially during rapid head movements. Postural instability is one of the prominent symptom associated with geriatric population and in many patients with neurological disorders like Stroke, Dementia, Parkinson's disease (PD), etc. Postural instability is one of the cardinal signs of PD. The instability leads to progressive reduction in both static and dynamic balance, resulting in recurrent falls.
Quantification of the postural balance of a person is necessary to assess the person's original medical problem and their rate of progress through rehabilitation or even through tele-rehabilitation. Therefore data capture and analysis, even while completing therapeutic activities (for example during functional movement tasks) can be used to provide information to therapist(s), optimize motional limit tasks and adaptively alter feedback settings and motional task difficulty. Measurement or quantification of stability is required to estimate severity of stroke, define treatment plan and monitoring progress of rehabilitation programs.
Further, the quantification of the postural balance in virtual environments or augmented reality based systems has become a need of the modern day health care due to increasing use of artificial intelligence and robotics in the field of medicines, healthcare, radio-activities and therapy activities. Modern day health care comprises, inter-alia, providing health care based upon use of tele-medicine facilities, health based applications and performing surgeries through robots. Augmented Reality (AR) comprises superimposition of a computer-generated image on a user's view of the real world to provide a composite view. AR may be implemented using a see-through stereoscopic display or by a see-through holographic or volumetric three-dimensional display. While being part of the virtual environment, a patient (or any person) can interact within a seemingly real or physical way, to use or manipulate objects or special electronic equipment. AR based systems superimpose digital information on top of the patient's real world (natural) view of his/her surrounding environment. AR may also add sound, graphics and haptics etc. to the real world view. Further, the AR based systems can provide a real-time feedback.
The traditional systems and methods provide assessment of postural stability using the AR based systems but none of them quantify or restrict the functional tasks performed by patient to a predefined level, instead, the patients are leveraged to accomplish it according to their capability. This leads to an unreliable or inaccurate stability assessment because each time the functional task level is unintentionally altered by the same patient, such as, the rising height of one leg in single-leg stance (SLS), the stability procedures are most likely to vary from trial to trial.